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Pinball Rehab

pinball repair and restoration

Repairing Backbox Corners Repairing Backbox Corners Hot

Remember that Samsonite commercial where a gorilla jumps up and down on someone's luggage at the airport?  I just picked up a Data East Hook pinball that must have been moved from location to location by the same gorilla.  Every corner on the backbox was heavily destroyed (see image 1).  In addition, on several corners the top layer of plywood was de-laminated (see image 2).

Normally if the wood was only slightly de-laminated (as compared to warped out about 1/2 an inch as it was on the Hook) I would use wood glue for the repair.  But in this case I felt safer using epoxy to bond the wood back in place.  In addition to some 5-minute epoxy I needed a way to hold the wood in place.

One of the handiest tools on the planet is a one-hand bar clamp, either the Irwin QuickGrip or the Wolfcraft One-Hand Bar Clamp.  Both are good choices and available at most hardware stores. In this case though, I didn't have one long enough to go across the backbox so I'll have to get a little creative.

The first step was to use a dental pick to pull any wood splinters out of the gap and trim the edges with an X-Acto knife.  Then I used toothpick to get plenty of epoxy into the gap.  I placed the quick-grip clamp from front to back on the backbox and slid a wood shim between the bar on the clamp and the loose piece of plywood to push it into place (see image 3).  After inserting the shim I wiped off any excess epoxy that was squeezed out, and ten minutes later I was ready to start patching.

In image 4 you can see the tools and supplies that I used to patch the backbox (see references after the article for more info on wood fillers and general wood patching techniques).  While small cabinet gouges can be repaired with wood putty, it's a good idea to use a product like JB Weld KwikWood Wood Repair Epoxy Putty on larger areas or ones that are vulnerable to damage, like corners and edges.

Image Gallery

Repairing Backbox Corners
Repairing Backbox Corners
Repairing Backbox Corners
Repairing Backbox Corners
Repairing Backbox Corners
Repairing Backbox Corners
Repairing Backbox Corners
Repairing Backbox Corners
Repairing Backbox Corners
Repairing Backbox Corners
Repairing Backbox Corners
Repairing Backbox Corners
Repairing Backbox Corners

In addition to various sizes of putty knifes, I've got a set of smaller tools that often come in handy when doing detailed touch-up.  You can pick these up at any hobby shop and they are especially helpful when doing playfield repair.  The last object in the photo is a block of wood that I wrap my sandpaper around to get a nice level finish.  You can also use a sanding block.

Corners are the most difficult type of cabinet repair since you're working in three dimensions instead of two. In Image 5 you can see where I've applied the epoxy.  I filled the area using a putty knife and then gently smoothed it out, leaving it slightly higher than the surrounding wood to account for shrinkage as it dries.

This approach takes some patience since the epoxy will push out one side while you're working on the other side.  It also requires more sanding since we're over-filling the damage.  The epoxy also hardens fairly quickly so you need to move fast.

I had to quickly move between the side, back and bottom of the backbox a couple of times before I was satisfied.  At the same time you also need to rub off any excess putty that has gotten on the paint outside of the repair area.  Just use your finger and a little spit if needed.  In Image 6 you can see the corners after sanding.

There is another method that works well, but its doesn't leave much room for shrinkage or sanding.

In Image 7 you can see where I've used my clamp and a piece of wood covered with wax paper to block off one side of the area I'll be patching.  Since the patch on that side will be flush with the backbox put the wood block on the side with the least damage.  The larger, or deeper, the area the more shrinkage you'll get.

Make sure you get the putty all the way down into the area behind the wood block.  Smooth the remaining side leaving it slightly higher than the wood.  In Image 8 and 9 I've sanded out the area and it looks pretty good, with a nice sharp corner and edges.

In Images 10, 11 and 12 you can see where I used the same approach to fill a gouge on the edge of the backbox.  In Image 13 you can see where I finally gave in and bought a longer set of clamps.